Two-cycle engine control



NOV. 26, 1935. F Q SHOEMAKER Er AL l2,022,094

TWO-CYGLE ENGINE CONTROL Filed Aug. 5, 1935 @-2 l @31.1 y www celeration A passage of carbureted fuel to the cylinders afterV Aof the engine.

Patented Nev. 2c. 1935 PMENTl OFFICE Two-CYCLE ENGINE coN'rnoL Fred G. Shoemaker, Ferndale, and Herbert F.

Baker, Detroit, Mich., signmcnts, to General assignors, by mesne as- Motors Corporation,

Detroit, Mich., a corporation of Delaware Application August 5, 1933, Serial No. 683,718

7 Claims.

This invention relates to two-cycle internal combustion engines and has particular. reference 4to a means for preventing the ingress of carbureted fuel to the ring chamber during the deperiod of the engine and to allow the the engine has slowed downto a good idling speed.

In the building of a two-cycle engine for use on automotive vehicles some difficulty has been experienced in obtaining a good idling operation of the engine where the vehicle is suddenly to be brought to a stop necessitating a slowing down down the engine the throttle is moved toward vclosed position to4 prevent further access of fuel to the engine. In ordinary two-cycle engines the throttle has'been allowed to remain open slightly so that when the engine has sufficiently slowed Adown -the slight crack of the throttle `will allow good idling. This partially open position of the throttle during deceleration was objectionable for the reason that it allowed the passage of a small amount offuel past the throttle during thedeceleration period of the engine. While this amount was not suiiicient to give a firing for each descent of the piston, nevertheless after two or three strokes there would be suiiicient fuel in the ring chamber to form a firing charge and there would be an objectionable firing when it was desired to decelerate. To obviate this difficulty and yet to allow for proper idling when the engine has suihciently decelerated, the structure of the present invention was devised. In accordance with the invention, when it is desired to decelerate the engine the throttle is immediately fully closed to prevent any further access of carbureted fuel. It is, however, impracticable to make a perfectly tight closure with a butterfly valve and there is always a slight leakage at the valve edge. To prevent this small amount of leakage gas from arriving at the cylinders, a passage to the atmosphere is opened simultaneously with the closing of the throttle. A valve to open the passage is operated atV the same time the throttle closed. 'I'his valve is to open the-passage to vent the cylinde'rs and cause the leakage gas to flow to the atmosphere instead of to the cylinders. When the engine has slowed down to a good idling speed, a centrifugal governor will cause the operaticn of the valve to close the vent to the atmosphei e and to open a bypass passage'around the throttle valve to allow a limited amount of carbureted mixture suiiicient for good idling to pass to the cylinders. This condition will continue until it is desired to accelerate the vehicle when the throttle As soon as it is desired to slow (Cl. 12S-65) valve is reopened to allow the engine to function in the usual way.

On the drawing Figure 1 is a sectional view through one cylinder of a multi-cylinder two-cycle internal com- 5 bustion engine, showing the invention applied.

Figure 2 is a View of a modification. Referring to the drawing, the numeral 2 indicates a two-cycle internal combustion engine as a whole. The engine may have any number of l0 cylinders, the drawing showing a section through but one of these ylinders.' The engine block is indicated at 4, an the removable engine head at 6. The water vcirculating system is indicated at 8 while I0 indicates the exhaust passages of the 15p i engine. Pistons are shown at I2 and operate in'cylinders I4 which are of U-type and have the common combustion chamber I6 whichl has the usual spark4 plug I8 to ignite the' mixture. The pistons I2 are connected by the connecting rods 20 20 to the crank shaft (not shown) operating in the crank case 22. The usual intake port is indicated at 24.

The parts so far described are conventional, and per se form no part of the invention. 1 25 At the intake side of. the'en'gine block 4 there is mounted the manifold system indicated asA a whole atp26. The manifold system comprises' the inlet manifold 28 having the riser 30 connectedV at 32 to a blower 34 of any suitable type shown 30 as comprising the two three-toothed members 36 driven by the connected gears 38. 0n the shaft of thelower gear 38 there is mounted a second gear 40 driven by a belt 46 vfrom the crank shaft of the engine in the well known way. The car- 35 I buretor (not shown) -is connected at 48 tothe inlet to the blower.

The manifold system 26 further comprises the. bypass passage 5.0 which has an entrance 52 into the riser 36 of the manifold at the lower or blower 40 side of the throttle 54. The passage 5U delivers at the outlet 56 onthe engine. side of the throttle 54. The major portion of the passage is` formed in a separate member 58 secured to the manifold 28 in any suitable way. 45

A suitable screw threaded element 60 is threaded into an opening 62 in the manifold 28 immediately above the outlet 56. The purpose of the element 60 is to regulate the size of the exit opening 56 of the passage 50. A lock nut 64 is used 50 to secure the element 60 in adjusted position. y The passage 50 has an opening or outlet 66 which opens to the atmosphere. The opening 66 and the entrance 52 to the passage 50 face each other and are controlled by a common valve 68. 55

The valve 68 has an elongated slidable stem 10v to the end of which there is secured a piston l12 which also forms the core of a solenoid 14. The solenoid has the helix or winding V"I6, suitably mounted, and an insulated head 18. ,A block 80 which may or may not, as desired, be of insulated material, forms the end portion of the solenoid 14 and serves to mount the solenoid on the member 58. A coil spring 82 is positioned between core piston 12 and the block 80 and constantly urges the valve and piston to the position shown in Figure 1. l Y

, Suitable wires 84 and 88 of an electriccircuit A allow for the passage of current through the winding cf the solenoid. 'niegwire u receives its current from a -suitable battery or other source-` indicated at 81, one of the .terminals ofthe bat` tery being connected to groundas at 88.

From the structure shown it is to be noted that the valve 68 is capable of; closing one only of the passages 52 and 86 at azjtime., In other words, the valve 68 is either inthe position shown in v' Figure 1, cr at the other-.extremity cf its sti-cke v'shaft 80 which hasa lever82 secured thereto to close the manifold entrance 82 tothe passage 50. A A

The throttle valve 84 ismounted on the usual outside the riser 80. A link 84 is connected at one end to the lever 82 and at its other end to a lever 86 rigidly secured to 'aV shaft 88 turnably mounted in a support |08 secured to the manifold 28. The shaft 88 has secured'thereto a lever |02 which has connected theretoa link |84 for the usual manual operation ofthe throttle 54,. If desired, the lever |82 may-be' secured gto the shaft 90.

The-shaft 88 has secured thereto an |88 having the screw |8 8 secured in the end thereof to form an adjustment for the operation ofthe arm l I0 of a bell cranklever ||2 pivotally mounted at bell crank lever has a ball end which operates in a slot in a sliding'pm m. .'rhepin m operates s spring contactfinger |24'andslides axially in a casing |22 suitably held on thev element 88. The contact nger |24 is suitably moimted on a plate f ofinsulating' material |28 and is adapted to makeV contact witha second spring contact finger |28 likewise mountedontheinsulatingplate |28. 'Ihe wire 86 of the circuit is connected to the contact |30 of the spring finger |28 while 'a wire |82 is clzczirinected to the contact |84 of the Spring met The wire I :z leads te c contact m ci contact -nger |38, apart of a centrifugal governor-'indicated as a whole at |48. The centrifugal governor is operated in any suitable way, such as by the gears |42 and |44 from the engine. One of the gears |42 has a shaft |48 which is operatedin any the finger on the axisof the shaft |88.- A third'` spring contact finger |88 is secured at one end by .a screw |88 to the governor and hasia welght|82 secured to the finger adjacent the other end. A

lead |88 connects Ythe miseri to'ground. 'A-

contact |84 on thennger v|88 is adapted to make with the contact |54 on-the ilnger |52 when governor attains a suillciently high speed.

Y The purpose of the electrical contact between' the ngers |24 and |28 is to make the electrical circuit indicated as a whole at A when the throttle is in fullyv closed position only as shown in Figure 1.V Whenv the throttle is fully closed (or inthe position of the parts shown in Figure l) the arm 5 |06 will move the bell crank lever I2 to push the pin |24 tothe right to make contact between the ends of the fingers |24 and |28. With the governor g rotating at suillciently high speed, the contact at gine-drops and the governor |40 is slowed down,

the weight |62 will :pull the contact |64 away from the contact |54 to break the circuit and deenergize the solenoid and cause the spring 82 to 20 push the piston 12 to the right to return the valve to the position shown in Figure 1., For positions of the throttle other than the closing position, the arm |88 will be 'swung in a counter-clockwise position vik) allow the spring finger |24 to throw the 25 pin`|28 and lever arm| |8 to the left to break the electrical connection between the contact nngers |24 and`|28. 'I 'his will keep the circuit A open at all times and hold the solenoid piston 12 and the valve 88intheposition shown inFigure 1. Itis 30 therefore evident4 that the solenoid and valve 88 are operative to clo theentrance 52 to the bypass passage when the throttle is in closed position only. Considering the position of the parts shownin 35 Figure 1, thisisthe position which corresponds' to the normalA idling of the engine. The engine l speed is such that the contact at |54, |84 of the centrifugalgovernorls open.l The loperation of 'the blower will force theI carbureted fuel up the a) riser 88 but as the throttle 54 is in closed position, thenormal passage of carbureted fuel into the engine will be prevented. However,- as the by- .pass passage 88 vis open it will allow a 'suilicient quantity cf tc pees thi-englische entrance 52 up the passage 5I and from the outlet56 to the firing chamber I8 to allow good idlingof the engine. If it is desired to increase the speed of the engine, the operator steps on the accelerator pedal to operate the rod |04 to open the throttle. 80

This immediat-.ely breaks the electricalconnec-l tion at contact fingers |24, |28 because of the movement ofthe-arm |88, and this break in the circuit A will assure that the solenoid will be retained in the position shown in Figurv'l, for as 8 8 the engineV speeds up the centrifugal governor will again make a connection between the 'conv tacts |84 and |84 to close the circuit at this point. .As the throttle opens,l ,the carbureted air may pass up the rlsertothe/firingchamberinthe usualw' way.` The bypass Ipassage .50, however, is still` open and carbureted fuel may pass therethrough tothe firing chamber but this is no disadvantage inasmuch as there is no desire-now to restrict any Aflow of passage tothe cylinder. 'I'he engine will 88' be speeded up andoperated at the desired rate of speed for the vehicle. Should the operator sight a' trame light in the distance which is just turning to halt the trailic in the direction in'which he Y is moving, he will remove his foot from the` ac- 70 solenoid now is energized and moves the valve 88 1l the engine.

'at 66 will relieve the cylinders of any undue pressure or compression and allow the engine easily to` slowdown for idling. The slowing down of the engine. of course, will slow down the speed of the centrifugal governor and when the governor speed corresponds to a good idlingspeed of the engine,

vthe contacts at |54, |64 will be broken to break the circuit to deenergize the solenoid to allow the spring 82 in the solenoid to move the piston 12 and valve 68 to the right to open the entrance 52 to the passage 50 and close the vent 66 to the atmosphere. This arrangement of parts will now open the bypass passage 50 and allow the entrance of suiicient carbureted fuel to give good idling of k, In Figure 2 there is shown a modification of the invention in which the bypass passage 50 is eliminated. The engine block is indicated at 28'. The manifold system has the manifold 28' and the riser 30 with which there is connected the usual blower and carburetor. The throttle-valve is indicated at 54' mounted on the usual shaft 90'. The shaft 90 has the 'usual lever secured thereto exteriorly of the manifold 28 in order that the throttle valve may be manually operated.4 There is secured to the shaft 90' an arm |80 which has an adjustable screw |02 secured to the end thereof. The end of the screw is separated from and adapted to contact with the end of a sliding rod |84 secured to a piston |86 forming the core of a solenoid |88. The solenoid has the usual helix or winding |90 and one end of the solenoid is closed by the plate |92 of insulating material While the other end is closed by the block |94 which may or may not be of insulating material. A spring |96 is provided in the solenoid between the piston |86 and the end of the block |94 and constantly urges the piston to the position shown inFigure 2. The solenoid has the contact |98 to which there .is connected the wire 200 of the electric circuit B. The contact |98 receives its current from the battery 86' one side of which is connected to ground at 88'. A second contact 2,02 on the solenoid has connected thereto a wire 204 leading to a contact l 36 on a centrifugal governor |40. The governor |40' distinguishes from the governor |40 in Figure 1 in that the contacts |54 and |64 on the spring contact fingers |52' and |58 are broken at higher governor speeds and made at lower governor speeds.

The operation of the structure of Figure 2 is as follows: considering that the speed of the vehicle is at what is termed higher speeds and the operator of the vehicle finds it necessary to slow down, he will raise his foot from the accelerator pedal which willA cause the throttle valve 54' to assume the closed position shown in Figure 2. The speed of the governor, however, still maintains the contacts |54', |64- separated so that the spring |96 will keep the piston |86 and rod |84 in the position shown in Figure 2. When the engine speed reaches a speed equivalent to good idling, the contacts at |54' and |64' will be made'to complete the circuit B to energize the solenoid |88 to cause it to pull the piston |86 to the left to cause the rodl |84 to operate the lever to crack the throttle 54' sufficiently to allow the passage of enough carbureted mixture to give a good idling speed to the engine.

We claim:

1. In a two-cycle internal combustion engine having an interrelated manifold, blower, and 5 throttle, manually operable means to operate the throttle,` an electric circuit, a contact in said circuit operated by the throttle operating means, said contact being closed when the throttle is in closed position only, a carbureted fuel passage 10 to allow carbureted fuel to pass around the throttle when the throttle is in closed position, said passage having an opening to the atmosphere, a 1 valve to Acontrol saidpassage, a solenoid in said circuit to operate said valve to closed position or 15 release it -for movement to opened position, and a governor in the circuit operated by the engine and maintaining said circuit closed at engine speeds above idling speed when the throttle is closed to cause said solenoid to keep said pas- 20 sage closed to the carbureted fuel and open to atmosphere to prevent carbureted fuel from entering the firing chamber and to allowin easy working of the pistons. 2. In a'two-cycle internal combustion engine, 25 an interrelated blower, manifoldsystem, and throttle, a. passage in the manifold system around the throttle, said passage being open to the atmosphere, a valve in the passage adapted to close the passage either to the atmosphere or tothe 30 manifold on the blower side of the throttle, means to operate said valve to close the opening to the atmosphere during any openv position of thev throttle and close the manifold opening during full throttle closed position 'for engine speeds 35 above ordinary idling speed, and means operated by the speed of the engine to control said firstnamed means. y y

` 3. In a two-cycle internal combustion engine, an interrelated blower, manifold system, and 40 throttle, a passage in the manifold syst/em around the throttle, said passage being open to the atmosphere, a valve in the passage adapted to close the passage either to the atmosphere or to the manifold on the 4blower side of the throttle, a 45" when the throttle is closed only, a second switch in the circuit, a governor operated bythe en- 50 gine to close the second switch at engine speeds above idling speed only to energize the solenoid to cause the solenoid to operate the valve to open the opening to the atmosphere when the throttle is closed, said governor opening the switch 55 at idling engine speed to break the circuit to deenergize the solenoid to cause the solenoid to release the valve to close the opening to the atmosphere when the throttle is closed.

4. In a two-cycle internal combustion engine 60 havingv an interrelated blower, manifold system, and throttle, a carbureted fuel passage in the manifold system around the throttle to allow.

. the engine to idle when the throttle is closed, said engine to idle when the throttle -fisclosed, passage having an opening to the atmosphere, a valve controlling both said openingY andthe yman ifold 4entrance to the passage, said valve always being in a'position to close one of said openings only, and means to control the position of the valve in accordance with the speed of, the engine and the position of the throttle.`

6. In a two-cycle internal combustion engine having an interrelated blower, manifold system, and throttle, a carbureted fuel passage in the manifold system around the throttle to allow the engine to idle when the throttlel'is closed,A said passage having an openingto' the atmosphere, a

valve controlling both said opening andthe manifold entrance to the passage, said. valve always being in a position to c lose oneiotsaid openings only at a time, and means including wgovernorv said.

to control the position o1' the valve in accordance with the speed of the engine and the position oi the throttle.

-'1. In a' two-cycle internal combustion engine having an interrelated blower, manifold system, and throttle, -a carbureted fuel passage in the manifold system around the throttle to allow the engine. to idle when the/throttle is closed, said passage having an opening to the atmosphere,

a valve controlling both said opening and the 10- manifold entrance to the passage, said valve always beingin a position to close one of said openings only, and means including a solenoid to control the position of the valve in accordance with the' 4speed'of the vengine and the position of 15 the throttle.

FRED G. SHOEMAKER.

T F. BAKER. 

